Why Does My EV Need 2 Charging Adapters? We Asked Adapter Manufacturer Lectron

There’s a reason most manufacturers won’t combine Level 2 and DC fast charging adapters into one device.

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Whether you’re new to EVs or an early adopter, you’ve had to deal with charging adapters. These handheld devices allow you to plug a Tesla into a standard home charger or DC fast charging station, or plug a non-Tesla vehicle into a Supercharger, Wall Connector, or Destination charger. You have to carry two of them in your car because the SAE-developed charging network uses different plugs for Level 2 and DC fast charging, whereas Tesla uses a single plug that does both. Why can’t there just be one adapter?

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Lectron Vortex adapter installed on a Tesla Supercharger plug.

The Answer is Safety

To find out, we asked charging adapter and EV charger manufacturer Lectron. CEO Christopher Maiwald and COO German Chan explained to us it’s a matter of safety, particularly when fast charging.

While Tesla elegantly designed a single plug, called NACS or J3400, to handle both Level 2 charging as well as DC Fast charging, the Society of Automotive Engineers (SAE) designed two separate plugs, the round J1772 Level 2 plug and the Combined Charging System (CCS) which adds two ports below the J1772 plug for DC fast charging. While the CCS connector incorporates the J1772 connector and can accept both, it requires separate plugs for each type of charging. As a result, the CCS plug on the vehicle functions like the NACS plug, but the connectors on the chargers are different.

(Level 2 charging uses 240-volt power and can be done at home or at public stations. DC fast charging uses up to 1,000 volts and can only be done at high-power public fast charging stations. Learn more with this explainer from our experts.)

Lectron Vortex adapter assembly.

Therefore, when converting from NACS to CCS and J1772, you need two adapters. Why not just combine them into one adapter, though? To do it right, the adapter would have to be massive. (NACS eliminates this problem within the charger itself by only powering the plug terminals associated with its power output.)

It’s a Matter of Switching

EVs are designed with integrated switches that detect whether a Level 2 or DC fast charger is plugged in, then make the connection to the appropriate onboard charging system. This is critical, because sending DC fast charging power to the Level 2 system would fry it and potentially start a fire. Charging adapters are designed to be passive pass-through modules so the EV treats them the same as if they weren’t there, allowing the onboard switch to work properly.

All the components of a Lectron Vortex adapter.

An adapter which lets both low- and high-power charging electricity pass through it, though, could accidentally send power to the wrong charging system and the car might not catch it. In order to ensure this doesn’t happen, a second switch would also need to be built into the adapter, and according to Maiwald and Chan, those switches are just too big and heavy to realistically fit in an adapter. Lectron’s adapters already weigh a couple of pounds, DC fast charging cables are heavy, and there’s only so much weight the plug can take. Adding a switch would make the adapter much bigger and heavier, which would make them harder to use and store in the vehicle as well.

Lectron Vortex adapter being driven over during a durability test.

What About the 2-in-1 Adapters on eBay?

Some companies do make 2-in-1 adapters without that switch, but you’ll notice they often don’t mention safety ratings. All Lectron adapters conform with Underwriter’s Limited (UL) standard 2252, which certifies safety, durability, and compatibility for EV charging adapters. (Lectron adapters are certified by third-party testing company SGS to the UL standard but are not UL Certified.) UL has made it clear it will not certify a 2-in-1 adapter without a switch, and Lectron won’t sell an adapter without a major third-party safety certification.

Lectron Vortex adapter undergoing water intrusion testing.

Those 2-in-1 adapters you do see on eBay often don’t mention safety certifications, or if they do, it’s other standards which aren’t as strict. That’s not the only thing odd about them, as their brands are almost impossible to Google. They don’t have websites, they don’t have independent reviews, and their certifications are likewise impossible to verify.

While they or may not work, the independent labs who test and certify adapters won’t touch them, and that says a lot. When hundreds of volts and amps and thousands of kilowatts are flowing, no one wants electricity going where it’s not supposed to. While both charging stations and EVs are designed to detect faults and short-circuits and stop charging before anything gets damaged or catches fire, the independent testing labs don’t like the idea of an adapter in between that doesn’t have the same capability and could even potentially confuse the vehicle or the charger.